This Connecticut-sized nation, sticking out like a loose tooth in the Persian Gulf, is one of the most obese nations in the world, with residents fatter, on average, than even those of the United States, which often takes the cake in such competitions.

According to recent studies, roughly half of adults and a third of children in Qatar are obese, and almost 17 percent of the native population suffers from diabetes. By comparison, about a third of Americans are obese, and eight percent are diabetic. Qatar also has very high rates of birth defects and genetic disorders -- problems that, along with the prevalence of obesity (PDF) and diabetes, have worsened in recent decades, according to local and international health experts.

So what's going wrong in little Qatar?

To misappropriate a well-worn phrase: It's the economy, stupid. In September, Qatar officially became the richest nation in the world, as measured by per capita gross domestic product. It also recently became the world's biggest exporter of natural gas, and earned the title of fastest growing economy in the world. By international development standards, all this growth has happened virtually overnight, making Qataris' lifestyles much more unhealthy, and at the same time leading many to hang on resolutely to what's left of their fleeting tribal traditions -- practices that include inter-marriage between close family members and cousins.

"They're concentrating the gene pool, and at the same time, they're facing rapid affluence," said Sharoud Al-Jundi Matthis, the program manager at the Qatar Diabetes Association, a government funded health center in Doha, the capital. As a result of these factors, Qataris are becoming obese, passing on genetic disorders at an alarming rate, and getting diabetes much more often than others around the world. They're also getting diabetes a decade younger than the average age of onset, which is pushing up rates of related illnesses and complications, like hypertension, blindness, partial paralysis, heart disease, and loss of productivity. "It's a very, very serious problem facing the future of Qatar," Matthis said.

Over the course of two generations, most native Qataris, who number only 250,000 in a nation of 1.7 million, and enjoy the benefits of a robust welfare state, went from living modest, tribal lifestyles in the Arabian desert, to living in air-conditioned villas with maids, nannies, gardeners, and cooks. Doha has mushroomed from a mere blip of beige buildings on a scorched spit of sand in the mid '90s, to a glistening glass metropolis populated by luxury hotels, fleets of shiny new Land Rovers, and fast food joints, where the young people huddle after school, sheltered from the famous Arabian heat, with temperatures hovering above 105 from late spring to late fall.

"Everybody in Qatar knows about diabetes, but the problem is, it's talking only. No one is taking care of it," said Adel Al-Sharshani, 39, who was diagnosed with diabetes several years ago. His father and several of his friends also have diabetes. "I ignored all the advice until it was too late, and that is what other people are doing too. It's dangerous." Because like many Qataris he got diabetes as a young man, Al-Sharshani knows he faces higher risk of complications, like blindness and paralysis. "I am afraid of losing my eyes, my foot. I am afraid of losing my life," he said.

Qatar is not alone in facing serious health problems. Its neighboring energy-rich states, including Kuwait, Bahrain, Saudi Arabia, and the United Arab Emirates, which also have conservative social traditions and have developed rapidly over the last five decades, face similar challenges with inter-familial marriage. High rates of obesity, diabetes, and genetic illnesses abound in the region.

According to the March of Dimes, Saudi Arabia ranked second globally for the number of birth defects per 1,000 births, while Qatar ranked 16th. A 2007 McKinsey report on the future of government-funded healthcare in the Gulf noted that the demand for hospital beds in Qatar is expected to increase by 100 percent by 2025. The six Gulf Cooperation Council countries are expected to increase their expenditures on health care by nearly 60 percent in that same time period.

In recent years, the Qatari government has implemented dozens of public awareness campaigns intended to educate Qatari adults and school children about healthy eating, exercise, fitness, and sports. More delicate cultural issues -- like coaxing tribal leaders to abandon familial inter-marriage -- are being addressed by "higher-ups in society," Matthis said. "Community leaders, sheikhs, people like that, are talking about those issues more and more."

The government has also implemented free and voluntary pre-marriage blood tests, which don't test for genetic links, but do warn potential spouses of genetic risks in their offspring. Most Qataris have a genetic predisposition for Type II diabetes, which increases the probability that their children will get the disease.

"Our main focus is encouraging people to be active, getting them to lead healthy lifestyles -- that's our vision," said Maher Safi, the marketing director at the Qatar Olympic Committee, the governmental entity that oversees nationwide fitness and sports programs in Qatar. In the past few years, the committee has launched public programs administering free body-mass indexes and sugar level tests, disseminated material about healthy eating, and introduced initiatives to schools to help children learn about new sports, like handball, tennis, and bicycling.

In cooperation with government-run health centers, the government of Doha has begun building parks, sidewalks, and pedestrian crossings in the city and residential neighborhoods, where at the moment it's virtually impossible to walk even between buildings without braving the sweltering, traffic-packed streets. Earlier this year, the government installed outdoor exercise equipment and automated bicycle rental kiosks on Doha's central boardwalk, which have gotten mixed reviews locally.

"You're not going to see Qatari ladies riding bikes," said Honey Stinnett, who was exercising on Doha's central boardwalk one night late September. She was raised in Malaysia, and says Qataris, most of whom follow the Wahhabi branch of Sunni Islam, are not culturally disposed to exercising outside. Most Qatari women wear floor-length black abayas, and many veil their faces. "Do you think you could exercise in that?" Stinnett said. "It's the culture that Qatari ladies are kept inside, where they are getting fatter and fatter."

A few paces away, a crowd of teenagers and young twenty-something men took turns on the bright yellow and red exercise equipment installed by the government in January. None of them were native Qataris, but they guessed why I was there.

"Because Qataris are fat!" said Hassan Tiaz, 19, laughing. He is Pakistani, but was born and raised in Qatar. He gestured to his own round belly. "It's because in Qatar, we just sit, smoke, and eat junk food. There's not too much work. Everything you have is automatic, and most of us just sit in air-conditioned offices and cars. Everything is done for us."

Tiaz's friend, Abdullah Rashid, 20, who wore a long white thobe to work out, blamed the culture of wealth. "Qataris are spoiled rich kids. Anytime they want to go out, they just get inside their car and go to the place," he said. Most Qataris think of those who sweat outside, like gardeners or construction workers, as lower-class people who must be hired and brought in from the outside.